Grinder



A. F. HOWE April 17, 1934.

GRINDER Filed March 14, 1928 2 Sheets-Sheet 1 I'll/III amen/3019'; Abvoezw F1 flan 5,

A. F. HOWE April 17, 1934.

GRINDER Filed March 14, 1928 2 Sheets-Sheet 2 GiAXW.

Patented Apr. 17, 1934 UNITED STATES 9 Claims.

This invention pertains to grinders and more particularly to grinders for grinding knives, such as butcher knives and the like.

One of the objects of this invention is to provide a grinder by means of which a knife may be quickly and accurately ground to any desired cutting edge.

Another object is to provide a device in which the knife may be mounted and which will guide the same with reference to the grinding element, so that a proper edge may be formed thereon.

Another object is to provide a grinder by means of which the curved tip of a butcher knife or the like may be ground to any desired radius.

Another object is to provide such a grinder which will be simple and cheap to construct, whichwill be rugged in service and which will be easy to disassemble for cleaning. Further objects will appear from the following 0 description, taken in connection with the accompanying drawings, in which 7 Figure l is a front view of a grinder embodying this invention Figure 2 is a section on line 2- -2 of Figure 1; Figure 3 is a partial plan view, taken about on line 3-3 of Figure 2;

Figure 4 is a fragmentary view, taken about on line 4--4 of Figure 3, showing the arrangement l for grinding the curved tip of a knife;

Figure 5 is a sectional view of the grinding element, taken on line 55 of Figure 2;

Figure 6 is a section of the knife holder, taken on line 6-6 of Figure 2. Figure '7 is a detail section on line 77 of Fig- "ure 6; and

Figure 8 is a diagram illustrating the various shapes of tips to which knives may be ground with this device.

Referring to the accompanying drawings, 1 designates a base, which may be formed of a suitable casting provided with feet so that it may stand on a bench or table. The base 1 is formed with a passage 2 running longitudinally through vthe middle thereof, In this passage, at its upper portion, there is formed a pair of guideways 3 adapted to receive outwardly extending ribs 4 formed on a carrier 5, which is supported thereby for movement in the passage 2. The carrier 5 is supported by the ribs 4 and slides longitudinally in the guideways 3.

The carrier 5 may be constructed of cast iron or other suitable material and has mounted therein a knife holder. The knife holder comprises a base portion 6, which has projecting from the front end thereof a pin 7 adapted to rest in a slot 8 in thefront wall of the carri er 5 and secured by a latch 70. The rearward portion of the base 6 rests on the head 9 of a pin 10 supported by a spring 11 enclosed in a suitable housing 12 in the carrier 5. The holder is loosely mounted in the carrier by means of these supports and is thus arranged so that it may be rocked from side to side on the pin '7 as a pivot, therear end being yieldinglysupported by the spring 11. The base portion 6 is of channel form and has mounted therein a pair of clamping plates 13 adapted to receive between them the knife blade 14 to be ground. The plates 13 are provided with inwardly directed lugs or fia'ng'es 15 (see Figure 6), whose lower surface is curved so as to permit the same to rock on their support within the base portion 6. Mounted between the plates 13, which are suitably chambered to receive the same, is a clamping bar 16, which rests on the lip-turned inner edges of the lugs or flanges 15. A clamping stud l7, suitably secured to the bar 16, passes downwardly through the base portion 6 and carries a wing nut 13 for tensioning the same. By means of this stud, a knife blade may be clamped between the plates 13 by screwing up the wing nut 18, which pulls the bar 16 downwardly against the flanges 15 so as to rock the plates 13 toward each other, as will be seen from Figure 6. The forward ends of the plates 13 are eiitended beydnd the rest of the holder and bent downwardly, as shown at 19, to provide a handle by means of which the holder may be manipulated. The downwardly turned portions 19 have mounted between them a spring 20, which tends to force them apart so as to yieldingly force the upper edges of the plates 13 together, so as to yieldingly hold a knife blade until it can be ad.- justed and then clamped by means of the nut 18.

Moun'tedon a bracket 21 hinged at 22 to the base 1 and secured by a spring-pressed dowel 23 is a motor 24. Mounted on the shaft 25 of the motor 24 is a pair of grinding wheels 26. As

will be seen from Figure 5, a sleeve 27 is suitably splined to the shaft 25 and has splined thereto a bushing 28. One of the wheels 26 is mounted on the bushing 28 and secured by a nut 29. Threaded on the end of the sleeve 27 and also on the shaft 25 is a bushing 30. This bushing has one of the wheels 26 mounted thereon and secured by a nut 31. A jam nut 32 on the shaft 25 secures the bushing 30 in adjusted position.

It will be seen that this construction provides for adjustment of the grinding wheels 26 relatively to the knife blade in the holder. By turning one of the wheels relatively to the other, the bushing 30 may be screwed in or out on the sleeve 2'7, thereby adjusting the spacing between the wheels 26. A spring 33 may be mounted between 5 the wheels in order to assist in keeping them in proper adjustment. By loosening the nut 32, the bushing 30 may be moved along the thread of the shaft 25 and thus the sleeve 27 may be adjusted along the shaft to adjust the wheels relatively 1G to the knife blade.

The pitch of the thread on the shaft 25 may be made one-half the pitch of the thread 300 which connects the bushing 39 with the sleeve 27. The effect of this arrangement is that when the bushing 30 is screwed upon the shaft it turns on two threads at once. Turning on the thread of the shaft 25 moves it to the left, Fig. 5, a distance per revolution equal to the pitch of that thread. At the same time this movement draws the bushing 27, which is splined on the shaft 25, to the right a distance, relatively to the bushing 30, equal to the pitch of the thread 300 which is twice the distance by which the bushing is moved to the left during the same rotation of said bushing. By this differential action of the two threads the wheels 25 are moved toward each other by equal amounts so that their distances from the knife blade 14 are maintained equal. In other words this adjustment keeps the ,wheels 26 centered with reference to the blade This adjustment of the wheels 26 provides for varying the distance between them so that the angle at which the knife blade engages each wheel may be adjusted as desired. Accordingly any desired taper may be ground on the knife edge. This adjustment may also be made to take up wear on the two grinding wheels.

Provision is made for grinding the curved end of a butcher knife or the like to any desired radius.

The base 1 is provided at its forward end with vertical channels or guideways 34:. A U-shaped yoke 35 is arranged to slide vertically in the guideways 34: and is held in adjusted position by a 4:5 spring-pressed dowel 36 adapted to engage any one of a series of index holes 3'? in the base 1. The yoke 35 carries a pair of inwardly projecting pivot pins 38. The carrier 5 is provided on its outer side faces at the rear end thereof with 59 a series of sockets 3's adapted to receive the pins '38 when the carrier is moved forwardly to the limit of its travel. The pivot pins 38 are placed in vertical alignment with the shaft 25 of the motor. The knife blade 14 is clamped in the holder such a way that the beginning of the curved portion 40 thereof is in vertical alignment with the rear of the slots or sockets 39. The adjustment of the yoke 35, by locating the same by means of the dowel 36, places the pivot pins 38 at such an elevation that, when the carrier 5 is moved forwardly, those pins will enter a pair of sockets 39. At the limit of the travel of the carrier, the pins 38 engage the ends/of the sockets 39 so as to arrest further movement. At this position, the ribs 4 have passed beyond the guideways 3 so as to become disengaged therefrom, and

the carrier may now be swung downwardly on the pins 38 as a pivot. This will carry the knife blade downwardly through an are such that its point of contact with the wheels 26 will describe a circular arc with the pivots 38 as the center (see Figure 4).

In the operation of this device, the knife 14 is clamped between the clamping plates 13 and ad- ,justed as previously described. During this operation, the holder may be removed from the carrier 5 by simply lifting it vertically therefrom. Upon being replaced, the knife blade 14 stands between the grinding wheels 26. The motor 24 is now started and the operator, grasping the handle 19, draws the carrier back and forth and rocks the knife holder to one side or the other, so as to bring the blade into engagement with the grinding wheels. In this way, either side of the straight part of the blade may be ground. At the end of the forward stroke, the pins 38 engage one pair of sockets 39, and from this point the operator may tip he carrier downwardly, at the same time holding the blade in engagement with the grinding wheel. This movement causes the blade to be ground in the arc of a circle at its tip. Both sides of the blade, both at its straight part and at its curved tip, may thus be ground without changing the adjustment of the blade in the holder. During the downward tipping movement of the carrier, the same is guided by a pair of forwardly projecting guide plates or fins 41, which prevent the lateral tipping of the carrier and render it easier to grind a true curve at the tip of the knife.

It will be seen that this device provides a convenient and effective means to grinding knives and the like. The knife may be adjusted to any desired position, so as to engage the grinding wheels in any desired way. The grinding wheels may be adjusted in their spacing as well as in their position laterally with respect to the movement of the knife holder. This adjustment provides for adjusting the angle at which the knife edge is ground. Any desired curvature may be given to the tip by simply adjusting the yoke 35 to its proper position as determined by the holes 37. Thus, either a long or short curve may be formed at the tip. The motor is mounted on a pivoted bracket, which may be swung out of the way at any time, so as to provide free access to the carrier.

While the device has been described as a unitary grinder, it will be understood, of course, that sub-combinations may be useful without respect to the rest of the device, and the use of such sub-combinations is contemplated by this invention. It is further obvious that various changes may be made, within the scope of the appended claims, in the details of construction without departing from the spirit of this invention; it is, therefore, to be understood that this invention is not limited to the specific details shown and described.

Having thus described the invention, what is claimed is:

1. A knife grinder, comprising, a base having a guideway, a knife holder movable in said guideway, grinding means positioned to engage a knife in said holder, means for pivoting said holder whereby the same may be rotated to grind the curved tip of the knife, and a movable mounting for said pivoting means for varying the pivot point in order to vary the curvature of the knife tip.

2. A knife grinder, comprising, a base having a guideway, a knife holder movable in said guideway, grinding means positioned to engage a knife in saidholder, a socket on said holder, and a pivot member engageable in said socket during the movement of said holder to permit pivotal movement of said holder in order to grind the curved tip of the knife.

3. A knife grinder, comprising, a base having a guideway, a knife holder movable in said guideway, grinding means positioned to engage a. knife in said holder, a plurality of sockets on said holder, and a pivot member engageable in any one of said sockets to permit a pivotal movement of said holder in order to grind the curved tips of knives having different curvatures.

4. A knife grinder, comprising a base having a fixed guideway, a knife holder movable longitudinally of the holder along said guideway, grinding means positioned to engage a knife in said holder, a pivot on said guideway, and a pivot socket on said holder normally free of said pivot but engageable therewith at the end of the travel of said holder, constructed and arranged to guide a knife blade longitudinally and thereafter pivotally in engagement with said grinding means.

5. A knife grinder, comprising a base having a fixed guideway, a knife holder movable longitudinally of the holder along said guideway, grinding means positioned to engage a knife in said holder, a pivot on said guideway, a plurality of variably spaced pivot sockets on said holder normally free of said pivot but engageable therewith at the end of the travel of said holder, and means for selectively positioning said pivot relatively to said sockets to engage a selected socket, constructed and arranged to guide a knife blade longitudinally and thereafter pivotally in engagement with said grinding means.

6. A knife grinder, comprising, a base, a knife holder adapted to support a knife for movement on said base, a grinding spindle, a pair of grinding elements movable on said spindle and positioned to engage opposite sides of a knife blade in said holder, and manipulating means adapted to move said elements simultaneously toward or away from each other.

7. A knife grinder, comprising, a base, a knife holder adapted to support a knife for movement on said base, a grinding spindle, a pair of grinding elements movable on said spindle and positioned to engage opposite sides of a knife blade in said holder, and a differential connection between said elements adapted for manipulation to move said elements simultaneously toward or away from each other.

8. In a grinder of the character described, a grinding spindle, a pair of grinding wheels mounted for rotation on said spindle and positioned to be engageable by a knife blade placed between them, and a differential connection between said wheels adapted for manipulation to move said wheels simultaneously toward or away from each other.

9. In a grinder of the character described, a grinding spindle, a pair of grinding wheels mounted for rotation on said spindle and positioned to be engageable by a knife blade placed between them, supports for said wheels, and differentially threaded means connecting said supports adapted for manipulation to move said wheels simultaneously toward or away from each other.

ANDREW F. HOWE. 

